Method and arrangement for white space device transmission

Abstract

The disclosure relates to a white space device (WSD) of a secondary wireless network, and to a related method for transmitting a first signal on a channel available for secondary usage allocated to a primary wireless system. The method in the WSD comprises determining (410) a further channel used by the primary wireless system, that would be interfered by a transmission of the first signal on the channel available for secondary usage, retrieving (420) signal information associated with the determined further channel from the primary wireless system, transmitting (430) the first signal on the channel available for secondary usage, and transmitting (440) a second signal on the determined further channel based on the retrieved signal information, simultaneously with the first signal on the channel available for secondary usage* such that an interference generated in the primary wireless system by the first signal transmission is compensated for by the second signal transmission.

The invention claimed is: 
     
       1. A method in a white space device of a secondary wireless system, for transmitting a first signal on a channel available for secondary usage allocated to a primary wireless system, the method comprising:
 determining a further channel used by the primary wireless system, that would be interfered by a transmission of the first signal on the channel available for secondary usage, 
 retrieving signal information associated with the determined further channel from the primary wireless system, 
 transmitting the first signal on the channel available for secondary usage, and 
 transmitting a second signal on the determined further channel based on the retrieved signal information, simultaneously with the first signal on the channel available for secondary usage, such that an interference generated in the primary wireless system by the first signal transmission is compensated for by the second signal transmission. 
 
     
     
       2. The method according to  claim 1 , wherein the signal information associated with the determined further channel is retrieved and stored during a period of low backhaul load. 
     
     
       3. The method according to  claim 1 , wherein determining the further channel comprises:
 transmitting a request for accessing the channel available for secondary usage to a control unit, the request comprising at least one of: parameters for estimating the interference generated in the primary wireless system by the first signal transmission; parameters related to a transmitting capability of the white space device; and a desired transmit power level for the first signal transmission; and 
 receiving information related to the further channel from the control unit in response to the transmitted request, the received information comprising an identity of the further channel and a required transmit power level for the second signal transmission on the further channel. 
 
     
     
       4. The method according to  claim 3 , wherein transmitting the first and second signals comprises gradually increasing a transmission power up to the desired and required transmit power levels respectively. 
     
     
       5. The method according to  claim 3 , wherein the white space device comprises the control unit. 
     
     
       6. A method in a control unit for supporting a white space device transmitting a first signal on a channel available for secondary usage allocated to a primary wireless system, the method comprising:
 receiving a request for accessing the channel available for secondary usage from the white space device, the request comprising at least one of: parameters for estimating the interference generated in the primary wireless system by the first signal transmission; parameters related to a transmitting capability of the white space device; and a desired transmit power level for the first signal transmission; 
 determining information related to a further channel used by the primary wireless system, wherein the further channel would be interfered by the first signal transmission on the channel available for secondary usage, the information being determined based on the received request and on parameters related to the primary wireless system available in the control unit, and the information comprising an identity of the further channel and a required transmit power level for a second signal transmission by the white space device on the further channel to compensate for interference caused on the further channel by the first signal transmission, and 
 transmitting the determined information to the white space device. 
 
     
     
       7. The method according to  claim 6 , wherein the control unit is a geo-location database unit. 
     
     
       8. A white space device configured to be used in a secondary wireless system, and to transmit a first signal on a channel available for secondary usage allocated to a primary wireless system, the white space device comprising:
 a processing unit configured to:
 determine a further channel used by the primary wireless system, that would be interfered by a transmission of the first signal on the channel available for secondary usage, and 
 retrieve signal information associated with the determined further channel from the primary wireless system, 
 
 a first transmitter for transmitting the first signal on the channel available for secondary usage, and 
 a second transmitter for transmitting a second signal on the determined further channel based on the retrieved signal information, simultaneously with the first signal on the channel available for secondary usage, such that an interference generated in the primary wireless system by the first signal transmission is compensated for by the second signal transmission. 
 
     
     
       9. The white space device according to  claim 8 , wherein the processing unit is configured to retrieve and store signal information associated with the determined further channel during a period of low backhaul load. 
     
     
       10. The white space device according to  claim 8 , wherein the processing unit is further configured to:
 transmit a request for accessing the channel available for secondary usage to a control unit, the request comprising at least one of: parameters for estimating the interference generated in the primary wireless system by the first signal transmission; parameters related to a transmitting capability of the white space device; and a desired transmit power level for the first signal transmission; and 
 receive information related to the further channel from the control unit in response to the transmitted request, the received information comprising an identity of the further channel and a required transmit power level for the second signal transmission on the further channel. 
 
     
     
       11. The white space device according to  claim 10 , wherein the first and second transmitters are configured to transmit the first and second signals by gradually increasing a transmission power up to the desired and required transmit power levels respectively. 
     
     
       12. The white space device according to  claim 10 , wherein the white space device comprises the control unit. 
     
     
       13. An apparatus operative as a control unit configured to support a white space device transmitting a first signal on a channel available for secondary usage allocated to a primary wireless system, the apparatus comprising:
 interface circuitry configured to receive a request for accessing the channel available for secondary usage from the white space device, the request comprising at least one of: parameters for estimating the interference generated in the primary wireless system by the first signal transmission; parameters related to a transmitting capability of the white space device; and a desired transmit power level for the first signal transmission; and 
 processing circuitry configured to:
 determine information related to a further channel used by the primary wireless system, wherein the further channel would be interfered by the first signal transmission on the channel available for secondary usage, the information being determined based on the received request and on parameters related to the primary wireless system available in the control unit, and the information comprising an identity of the further channel and a required transmit power level for a second signal transmission by the white space device on the further channel to compensate for interference caused on the further channel by the first signal transmission, and 
 transmit the determined information to the white space device, via the interface circuitry. 
 
 
     
     
       14. The apparatus according to  claim 13 , wherein the apparatus is configured as a geo-location database unit.